The present invention is directed to bicycles and, more particularly, to a bicycle sprocket apparatus with reinforcement between sprockets.
Many bicycles have derailleur operated transmissions. Such transmissions usually include a plurality of front sprockets and a plurality of rear sprockets, wherein the plurality of front sprockets are mounted for rotation coaxially with the pedal cranks, and the plurality of rear sprockets are mounted for rotation coaxially with the rear wheel. A front derailleur is mounted to the bicycle frame in close proximity to the plurality of front sprockets to selectively engage a chain with one of the plurality of front sprockets, and a rear derailleur is mounted to the bicycle frame in close proximity to the plurality of rear sprockets to selectively engage the chain with one of the plurality of rear sprockets. A shift control device operated by the rider may manually or automatically control the front and rear derailleurs.
Adjacent pairs of the plurality of front or rear sprockets may be connected together by a sprocket support that comprises a plurality of radially extending mounting arms. Each mounting arm includes a sprocket mounting portion disposed between its corresponding pair of sprockets, and a fastener is used to fasten the pair of sprockets to the mounting portion. The number of mounting arms must be sufficient to firmly mount the sprockets to withstand the rotational force of the chain and to prevent lateral bending of the sprockets. On the other hand, it also is desirable to minimize the number of mounting arms to save weight. While a smaller number of mounting arms may sufficiently accommodate the rotational force of the chain, reducing the number of mounting arms also reduces lateral support between the sprockets, thus increasing the risk of lateral deflection of the sprockets caused by the chain.